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US 5,290,827 AGranted
Precipitation of homogeneous polymer mixtures from supercritical fluid solutions
AssigneeUniversity of Delaware
InventorAnnette D. Shine
Life of this patent
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Abstract
Homogeneous polymer blends are prepared from otherwise thermodynamically immiscible polymers. Thus, mixtures of polymers such as poly (methyl methacrylate) and poly (ethyl methacrylate) are dissolved under pressure in supercritical fluid solvents such as chlorodifluoromethane and expanded through a fine nozzle. As the SCF solvent evaporates, the polymer mixture deposits as a substantially homogeneous blend.
Claims8
A process for preparing a homogeneous blend of otherwise thermodynamically immiscible polymers, comprising:
- a) preparing a solution of said polymers in a supercritical fluid solvent to form a single-phase solution blend;,
- b) rapidly expanding the solution from step (a) across a small diameter nozzle;
- and
- c) removing said supercritical fluid solvent to precipitate the solid polymer blend at a final temperature which is no more than about 30.degree. C. above the glass transition temperature of the polymer blend, whereby, the non-equilibrium homogeneous morphology of the blend is maintained.
1 more element
Dependencies are inferred from the claim text.